Some heavy duty trucks are composed of a tractor and one or more trailers coupled in series to the rear portion of the tractor. Typically, a trailer is provided with air brakes on its wheels. The air brakes require the connection of air lines extending from an air compressor on the tractor cab to the wheel brakes of the trailer. Normally, tractors and trailers can be interchanged as modular units so that a fleet of tractor cabs and a fleet of trailers can be used interchangeably.
To facilitate the interchangability, the hitches for the tractors and trailers are standardized. The Society of Automotive Engineers (SAE) standard J318 has served the purpose of providing a standard for coupler halves for brake lines on a vehicle that will be identified and compatible with the coupler halves on the brake lines of another vehicle. The SAE standard J318 is, therefore, specifically dedicated to automotive air brake line couplers (also known as gladhands). In addition, the J318 standard provides design, interchangeability dimensions, testing procedures, performance requirements, and minimum identification for gladhand-type air line couplers used to connect the brake systems of trucks, truck-tractors, trailers, and dollies when these vehicles are joined to operate in combination as a unit. The SAE standard J318 is incorporated herein by reference.
The standard gladhand is adapted to serve as a quick connect and disconnect coupling for the two high-pressure air brake hoses which are known as service (or signal) and emergency hoses. A complete gladhand connection is composed of a pair of essentially identical gladhands. The face-abutted gladhands are fully mated by turning one relative to the other until a stop or lock of some sort is reached. The use of gladhands provides a quick means for establishing pneumatic communication between, for example, air brakes of the trailer and the pump on the truck cab.
Normally, a gladhand includes a coupler and a clamp. The coupler typically has a fan-like flange at one end and an opening at the opposite end. The opening leads to an internal air channel which ends at a second opening on the face of the coupler. The opening on the face is typically surrounded by a resilient member. When two face-abutted gladhands are fully mated by turning one on the other, their respective resilient members abut together while the clamp of one gladhand is locked into the flange of the other, and vice versa. Typically, the main body of a gladhand is made of aluminum.
The clamp of the gladhand is usually made of a thin piece of powder coated steel to provide some flexibility when two gladhands are mated. Normally, the clamp is attached to the coupler by a pair of spaced bolts and nuts. However, the thin piece of powder coated steel tends to wear out very quickly, or can be bent from its desired position, with the frequent coupling and uncoupling of the gladhands. This can result in air leakage when two gladhands are mated. In addition, the pair of bolts and corresponding nuts that hold the clamp to the coupler may loosen up over time, which in turn can also allow air to leak through the seal formed by the mating faces of the gladhands.
Some gladhands include a mounting bracket to allow the gladhands to be mounted to a tractor or a trailer. Typically, the bracket is mounted so as to be proximate to the break air hose associated with a tractor or trailer. In order to facilitate the coupling of this type of gladhand with another, the gladhand may be designed to be able to swing (i.e., pivot) along an axis supported by the bracket. To prevent a mating air hose from being damaged as the gladhands are pivoted, the mating air hoses are provided with a live swivel fitting at their mating end. However, the live swivel fitting provided in the mating air hose tends to be of relatively poor quality, resulting in frequent air leaks in the brake system.
Accordingly, there is a need for an improved gladhand which includes a durable clamp for increased life expectancy of the gladhand. In addition, there is a need for an improved swivel-type gladhand which does not require the use of an air hose with a live swivel fitting so as to mitigate leakage at the connection between the air hose and the gladhand and thereby improve the overall integrity of the pneumatic braking system.